1. Field of the Invention
The present invention relates to an autofocus adjustment method and a corresponding device for a camera. The autofocus adjustment method and device can accurately focus on a moving object.
2. Description of Related Art
Autofocus devices are known, such as in Japanese Unexamined Patent Applications Hei 2-50140 and Hei 5-107455, which can calculate the image plane movement velocity. The lens movement amount for a lens control is calculated from the image plane movement velocity. Additional autofocus devices are known, such as in Japanese Unexamined Patent Applications Sho 62-125311 and Sho 62-139511, which can determine the movement of an object from the lens movement amount change.
The image plane's movement velocity indicates the image plane's position velocity change, if the lens is fixed. If the lens is not fixed but varies, the image plane's movement velocity varies. Errors can occur when the image plane's movement velocity is converted by a defocus amount lens movement amount conversion coefficient for moving the lens to focus. Also, the determination whether a body is moving, from the change in the lens movement amount, does not provide an accurate determination of the body's status because lens movement amount varies according to the lens focus adjustment process.